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ca01d6dd TL |
1 | /* |
2 | * Persistent Storage - platform driver interface parts. | |
3 | * | |
4 | * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
19 | ||
20 | #include <linux/atomic.h> | |
21 | #include <linux/types.h> | |
22 | #include <linux/errno.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/kmsg_dump.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/pstore.h> | |
27 | #include <linux/string.h> | |
28 | #include <linux/slab.h> | |
29 | #include <linux/uaccess.h> | |
30 | ||
31 | #include "internal.h" | |
32 | ||
33 | /* | |
34 | * pstore_lock just protects "psinfo" during | |
35 | * calls to pstore_register() | |
36 | */ | |
37 | static DEFINE_SPINLOCK(pstore_lock); | |
38 | static struct pstore_info *psinfo; | |
39 | ||
dee28e72 MG |
40 | static char *backend; |
41 | ||
366f7e7a | 42 | /* How much of the console log to snapshot */ |
ca01d6dd TL |
43 | static unsigned long kmsg_bytes = 10240; |
44 | ||
366f7e7a | 45 | void pstore_set_kmsg_bytes(int bytes) |
ca01d6dd | 46 | { |
366f7e7a | 47 | kmsg_bytes = bytes; |
ca01d6dd TL |
48 | } |
49 | ||
ca01d6dd TL |
50 | /* Tag each group of saved records with a sequence number */ |
51 | static int oopscount; | |
52 | ||
9f6af27f TL |
53 | static char *reason_str[] = { |
54 | "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency" | |
55 | }; | |
56 | ||
ca01d6dd TL |
57 | /* |
58 | * callback from kmsg_dump. (s2,l2) has the most recently | |
59 | * written bytes, older bytes are in (s1,l1). Save as much | |
60 | * as we can from the end of the buffer. | |
61 | */ | |
62 | static void pstore_dump(struct kmsg_dumper *dumper, | |
63 | enum kmsg_dump_reason reason, | |
64 | const char *s1, unsigned long l1, | |
65 | const char *s2, unsigned long l2) | |
66 | { | |
67 | unsigned long s1_start, s2_start; | |
68 | unsigned long l1_cpy, l2_cpy; | |
69 | unsigned long size, total = 0; | |
9f6af27f | 70 | char *dst, *why; |
ca01d6dd | 71 | u64 id; |
b94fdd07 MG |
72 | int hsize; |
73 | unsigned int part = 1; | |
ca01d6dd | 74 | |
9f6af27f TL |
75 | if (reason < ARRAY_SIZE(reason_str)) |
76 | why = reason_str[reason]; | |
77 | else | |
78 | why = "Unknown"; | |
79 | ||
ca01d6dd TL |
80 | mutex_lock(&psinfo->buf_mutex); |
81 | oopscount++; | |
82 | while (total < kmsg_bytes) { | |
83 | dst = psinfo->buf; | |
56280682 | 84 | hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part); |
ca01d6dd TL |
85 | size = psinfo->bufsize - hsize; |
86 | dst += hsize; | |
87 | ||
88 | l2_cpy = min(l2, size); | |
89 | l1_cpy = min(l1, size - l2_cpy); | |
90 | ||
91 | if (l1_cpy + l2_cpy == 0) | |
92 | break; | |
93 | ||
94 | s2_start = l2 - l2_cpy; | |
95 | s1_start = l1 - l1_cpy; | |
96 | ||
97 | memcpy(dst, s1 + s1_start, l1_cpy); | |
98 | memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); | |
99 | ||
56280682 MG |
100 | id = psinfo->write(PSTORE_TYPE_DMESG, part, |
101 | hsize + l1_cpy + l2_cpy, psinfo); | |
9f6af27f | 102 | if (reason == KMSG_DUMP_OOPS && pstore_is_mounted()) |
ca01d6dd TL |
103 | pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, |
104 | psinfo->buf, hsize + l1_cpy + l2_cpy, | |
638c1fd3 | 105 | CURRENT_TIME, psinfo); |
ca01d6dd TL |
106 | l1 -= l1_cpy; |
107 | l2 -= l2_cpy; | |
108 | total += l1_cpy + l2_cpy; | |
56280682 | 109 | part++; |
ca01d6dd TL |
110 | } |
111 | mutex_unlock(&psinfo->buf_mutex); | |
112 | } | |
113 | ||
114 | static struct kmsg_dumper pstore_dumper = { | |
115 | .dump = pstore_dump, | |
116 | }; | |
117 | ||
118 | /* | |
119 | * platform specific persistent storage driver registers with | |
120 | * us here. If pstore is already mounted, call the platform | |
121 | * read function right away to populate the file system. If not | |
122 | * then the pstore mount code will call us later to fill out | |
123 | * the file system. | |
124 | * | |
125 | * Register with kmsg_dump to save last part of console log on panic. | |
126 | */ | |
127 | int pstore_register(struct pstore_info *psi) | |
128 | { | |
129 | struct module *owner = psi->owner; | |
130 | ||
131 | spin_lock(&pstore_lock); | |
132 | if (psinfo) { | |
133 | spin_unlock(&pstore_lock); | |
134 | return -EBUSY; | |
135 | } | |
dee28e72 MG |
136 | |
137 | if (backend && strcmp(backend, psi->name)) { | |
138 | spin_unlock(&pstore_lock); | |
139 | return -EINVAL; | |
140 | } | |
141 | ||
ca01d6dd TL |
142 | psinfo = psi; |
143 | spin_unlock(&pstore_lock); | |
144 | ||
145 | if (owner && !try_module_get(owner)) { | |
146 | psinfo = NULL; | |
147 | return -EINVAL; | |
148 | } | |
149 | ||
150 | if (pstore_is_mounted()) | |
151 | pstore_get_records(); | |
152 | ||
153 | kmsg_dump_register(&pstore_dumper); | |
154 | ||
155 | return 0; | |
156 | } | |
157 | EXPORT_SYMBOL_GPL(pstore_register); | |
158 | ||
159 | /* | |
160 | * Read all the records from the persistent store. Create and | |
161 | * file files in our filesystem. | |
162 | */ | |
163 | void pstore_get_records(void) | |
164 | { | |
165 | struct pstore_info *psi = psinfo; | |
8d38d74b | 166 | ssize_t size; |
ca01d6dd TL |
167 | u64 id; |
168 | enum pstore_type_id type; | |
169 | struct timespec time; | |
06cf91b4 | 170 | int failed = 0, rc; |
ca01d6dd TL |
171 | |
172 | if (!psi) | |
173 | return; | |
174 | ||
175 | mutex_lock(&psinfo->buf_mutex); | |
06cf91b4 CG |
176 | rc = psi->open(psi); |
177 | if (rc) | |
178 | goto out; | |
179 | ||
638c1fd3 | 180 | while ((size = psi->read(&id, &type, &time, psi)) > 0) { |
8d38d74b | 181 | if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size, |
638c1fd3 | 182 | time, psi)) |
ca01d6dd TL |
183 | failed++; |
184 | } | |
06cf91b4 CG |
185 | psi->close(psi); |
186 | out: | |
ca01d6dd TL |
187 | mutex_unlock(&psinfo->buf_mutex); |
188 | ||
189 | if (failed) | |
190 | printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", | |
191 | failed, psi->name); | |
192 | } | |
193 | ||
194 | /* | |
195 | * Call platform driver to write a record to the | |
196 | * persistent store. | |
197 | */ | |
198 | int pstore_write(enum pstore_type_id type, char *buf, size_t size) | |
199 | { | |
200 | u64 id; | |
201 | ||
202 | if (!psinfo) | |
203 | return -ENODEV; | |
204 | ||
205 | if (size > psinfo->bufsize) | |
206 | return -EFBIG; | |
207 | ||
208 | mutex_lock(&psinfo->buf_mutex); | |
209 | memcpy(psinfo->buf, buf, size); | |
56280682 | 210 | id = psinfo->write(type, 0, size, psinfo); |
ca01d6dd TL |
211 | if (pstore_is_mounted()) |
212 | pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf, | |
638c1fd3 | 213 | size, CURRENT_TIME, psinfo); |
ca01d6dd TL |
214 | mutex_unlock(&psinfo->buf_mutex); |
215 | ||
216 | return 0; | |
217 | } | |
218 | EXPORT_SYMBOL_GPL(pstore_write); | |
dee28e72 MG |
219 | |
220 | module_param(backend, charp, 0444); | |
221 | MODULE_PARM_DESC(backend, "Pstore backend to use"); |